#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 40;
ll c[N][N];
int main(){
    for(int i = 0; i < N; i++){
        for(int j = 1; j <= i; j++)
        if(!j)c[i][j] = 1;
        else
            c[i][j] = c[i-1][j] + c[i-1][j-1];
    }
    int n; 
    cin >> n;
    cout << c[n*2][n]/(n+1) << endl;
    return 0;
}